I must confess - aside from knowing there was a difference, I didn’t really know what the difference was until a few online searches yesterday.
The understanding I have is that winter/summer gas programs began in the late 1980’s.
My supposition is that they have been handled seamlessly to the point that unless you are involved in regulation or the industry, it’s relatively inconsequential to most folks. I imagine knowledge of the program’s existence is probably one of those things that people sorta ignore unless it randomly becomes a topic of conversation. (Like any number of random regulations that impact our daily lives that we just don’t think about most of the time.)